Wiktionary
n. (context gaming English): A character in a role-playing game whose actions are controlled by a player.
Wikipedia
A player character or playable character (PC) is a fictional character in a role-playing or video game whose actions are directly controlled by a player of the game rather than the rules of the game. The characters that are not controlled by a player are called non-player characters (NPCs). The actions of non-player characters are typically handled by the game itself in video games, or according to rules followed by a gamemaster refereeing tabletop role-playing games. The player character functions as a fictional, alternate body for the player controlling it.
Video games typically have one player character for each person playing the game. Some games offer a group of player characters for the player to choose from, allowing the player to control one of them at a time. Where more than one player character is available, the characters may have different abilities, strengths, and weaknesses to make the game play style different.
Usage examples of "player character".
For play balance, the DM should place a 1st-level player character as only one of several counselors to a lord of a small domain--perhaps a knightly manor or a barony.
Only in very rare cases-such as a low-level character being transported into the Outer Planes, for example-should a player character ever be given the ability to wield spellfire.
Each Player Character shall chose the same inn (the White Unicorn), despite any other preferences they may have (if they persist in choosing another inn, then that one is full, or under repair, or even burns down if necessary).
He is still quite in love, though, and a concerned player character can eventually talk him into facing her.